Jet stream generating method and apparatus

ABSTRACT

A condensing system is provided. The condensing system may include baffle plate units having a substantially flat surface and openings configured for cooling fluid to flow through; and baffles attached to the baffle plate unit, the baffles oriented at an acute angle with respect to the baffle plate unit, the baffles having a flat surface and figured to diffuse a cooling fluid into a thin, turbulent film at a similar acute angle. A method of condensing a fluid is provided. The method includes defining a path for the fluid to be condensed to flow; spraying a cooling fluid against a baffle thereby creating a turbulent film of cooling fluid in the path for the fluid to be condensed and orienting some of the baffles to create a film of cooling fluid oriented in one direction and orienting other baffles to create a film of cooling fluid in a second direction wherein the path of the fluid to be condensed causes the fluid to be condensed to flow over films oriented in both the first and second directions.

FIELD OF THE INVENTION

The present invention relates generally to a method and apparatus forcondensing a fluid. More particularly, the present invention relates toa spray system for direct contact condensers.

BACKGROUND OF THE INVENTION

Due to the increasing water shortages all over the world, an increasingnumber of the new, large capacity thermal power plants are equipped withair-cooling systems.

There are two main versions of air-cooling systems suitable for powerplant cooling, the direct steam condensing in an air cooled condenser,(ACC) and the indirect cooling tower (IDCT) cooling systems. In thedirect ACC system the exhaust steam of the steam turbine is introducedinto the air cooled steam-air heat exchangers of a mechanical draftcooling tower, whereas the indirect IDCT system uses water cooledcondensers (surface or direct contact types), and the warmed coolingwater is introduced into the water-air heat exchangers of a mechanicalor natural draft cooling tower. The subject of the present invention isrelated to an advanced spray system of the direct contact (DC)condensers of large capacity indirect IDCT cooling plants

Except the first filling up of the circulating water system, IDCT plantsusually don't need any cooling water make up for their operation duringthe life-time of the power plant they serve. The water to be used forthe first filling of the cooling system can be taken from the watertreatment plant of the power station, therefore its quality can be thesame as that of the feed water of the boiler-turbine circuit.Consequently the cooling water and the steam condensate can be mixed inthe condenser, which means that for IDCT plants direct contact, DCcondensers can be used.

In DC condensers there are no expensive titanium or stainless steeltubes, the heat from the condensing steam is transferred to the sprayedin cooling water by thin, turbulent water films, produced by the spraysystem of the condenser. The heat transfer coefficient between thecondensing steam and the turbulent water films is extremely high, in therange of 60,000-70,000 W/m²K, whereas that in case of surface condensersis 6000-7000 W/m²K only.

High heat transfer coefficient means small terminal temperaturedifference (TTD) in the DC condenser. With well-designed spray system0.5-0.8° C. TTD can be achieved with DC condensers and with surfacecondensers with economically fair design 3-5° C. can be reached only. A1° C. decrease in the TTD means 3.3% saving in the investment cost ofthe whole cooling plant, therefore in case of the above mentionedexamples 8.2-13.8 saving in the investment cost is expected by the useof DC condensers instead of surface types.

The cost of the DC condenser itself is about 1/10 that of the surfaceones. The above examples well illustrate the importance of awell-designed spray system of the DC condensers.

Accordingly, it is desirable to provide an effective and efficientcooling system.

SUMMARY OF THE INVENTION

The foregoing needs are met, to a great extent, by the presentinvention, wherein in one aspect an apparatus is provided that in someembodiments provide an efficient cooling system.

In accordance with one embodiment of the present invention, a spraysystem is provided. The spray system may include a baffle plate unithaving a substantially flat surface and openings configured for coolingfluid to flow through; and baffles attached to the baffle plate unit,the baffles oriented at an acute angle with respect to the baffle plateunit, the baffles having a flat surface and figured to diffuse a coolingfluid into a thin film at a similar acute angle.

In accordance with another embodiment of the present invention, a spraysystem is provided. The spray system may include a means for supporthaving a substantially flat surface and openings configured for coolingfluid to flow through; and means for diffusing a fluid attached to themeans for support, the means for diffusing at an acute angle withrespect to the means for support, the means for diffusing having a flatsurface and figured to defuse a cooling fluid into a thin film at asimilar acute angle.

In accordance with yet another embodiment of the present invention, amethod of condensing a fluid is provided. The method includes defining apath for the fluid to be condensed to flow; spraying a cooling fluidagainst a baffle thereby creating a film of cooling fluid in the pathfor the fluid to be condensed to flow at an acute angle with respect tothe flow path of the fluid to be condensed; and orienting some of thebaffles to create a film of cooling fluid oriented in one direction andorienting other baffles to create a film of cooling fluid in a seconddirection wherein the path for the fluid to be condensed causes thefluid to be condensed to flow over films oriented in both the first andsecond directions.

There has thus been outlined, rather broadly, certain embodiments of theinvention in order that the detailed description thereof herein may bebetter understood, and in order that the present contribution to the artmay be better appreciated. There are, of course, additional embodimentsof the invention that will be described below and which will form thesubject matter of the claims appended hereto.

In this respect, before explaining at least one embodiment of theinvention in detail, it is to be understood that the invention is notlimited in its application to the details of construction and to thearrangements of the components set forth in the following description orillustrated in the drawings. The invention is capable of embodiments inaddition to those described and of being practiced and carried out invarious ways. Also, it is to be understood that the phraseology andterminology employed herein, as well as the abstract, are for thepurpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conceptionupon which this disclosure is based may readily be utilized as a basisfor the designing of other structures, methods and systems for carryingout the several purposes of the present invention. It is important,therefore, that the claims be regarded as including such equivalentconstructions insofar as they do not depart from the spirit and scope ofthe present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a steam turbine with twin DC condensers.

FIG. 2 is partial cross-section view of a DC condenser.

FIG. 3 is a partial cross-sectional view taken along the 3-4 in FIG. 2.

FIG. 4 is a partial cross-sectional view taken along the 3-4 in FIG. 2.

FIG. 5 is a perspective view of a baffle plate in accordance with anembodiment of the invention.

FIG. 6 is a cross-sectional view of the side wall of the waterdistributing chamber, together with the section of the spray nozzles andbaffle plates in a DC condenser in accordance with the invention.

FIG. 7 illustrates an arrangement and design of the spray nozzles andbaffle plate in accordance with an embodiment of the invention.

FIG. 8 is a cross-sectional view of the spray nozzles and baffle platestaken along line 8-8 shown in FIG. 7.

DETAILED DESCRIPTION

The invention will now be described with reference to the drawingfigures, in which like reference numerals refer to like partsthroughout. An embodiment in accordance with the present inventionprovides a spray system, which allows the design of a compact and moreefficient condenser type than the currently used ones, and spraynozzles, which apart from fulfilling the thermo-technical requirementsare less expensive than the currently known spray nozzles and can bemanufactured with modern, highly productive automatic machine tools.

FIG. 1 shows a steam turbine 10. Twin condensers 12 are attached to theturbine. The condensers 12 are used to condense the steam by forcing thesteam to flow over and exchange heat with a cooling fluid. While steamis described herein as the fluid to be condensed, the invention is notlimited to steam. Other fluids could also be condensed using principlesdescribed herein.

While water is described herein as the cooling fluid, the invention isnot limited to water. Other fluids could be used as the cooling fluidusing principles described herein.

The turbine 10 includes high pressure 14, medium pressure 16 and lowpressure 18 cylinders. The turbine 10 and generator 20 are mounted on asupport frame 22. The turbine 10 is operatively connected a generator 20for generating electricity. Other embodiments of the invention may beapplied to cooling devices that may or may not be associated with aturbine 10.

The low pressure turbine 18 has a double exhaust system, therefore twosimilar DC condensers 12, one right and one left, are connected via twodiffusers or connecting conduit 24 to the exhaust parts of the turbine10. In some embodiments the two condensers 12 are very similar or thesame as each other. Thus, only one condenser 12 will be explained indetail. The condenser 12 will be described later further below.

Cooling water enters the condenser 12 through a cold cooling water inletnozzle 28, and warmed cooling water leaves the condenser body 26 througha warm cooling water outlet nozzle 30. The condensers 12 are supportedby spring 29 supporting pieces 31, which allow free heat expansionmovements both horizontally and vertically.

The simplified structure of a DC condenser 12 equipped with the spraysystem is accordance with the present invention is illustrated on FIG.2. Some features of the condenser 12 not relevant or are known are notshown in order to avoid crowding of the FIGS.

In FIG. 2 the fabricated condenser body 26 has, as an example fourcooling water distributing chambers 32. More or fewer cooling waterdistributing chambers 32 could also be used. The cooling waterdistributing chambers 32 on the right of FIG. 2 and vertical steam paths54 are shown with several features removed to avoid over crowding ofFIG. 2. The cooling water distributing chambers 32 and vertical steampaths 54 between the water films on the left shown more detail. Steam tobe condensed enters the condenser 12 through the steam inlet 56. Thesteam then travels through the steam paths 59 in the directions shown bythe arrows in FIG. 2.

The steam is condensed as it passed over the films 52 of cooling fluid.The films 52 are fan shaped as shown in FIG. 2. Once the steam hascontacted the water films, some or all of the steam may condense intowater and collect into the hot well 48. Line 50 illustrates a waterlevel in the hot well 48. The water may leave the hot well 48 via thewarm cooling water outlet nozzle 30.

An air cooling section 34 is connected to the bottom part of eachdistributing chamber 32. A vent pipe 36 transfers the remainingsteam/air mix towards vacuum pump (not shown in FIG. 2) of the steamturbine 10. Perforated trays 38 form a counter flow cascade air-coolingheat exchanger.

The spray nozzles 42 in the air cooling section 34 spray cooling waterinto the steam air mix. Then the cooling water films drop onto thetopmost perforated trays 38 of the air cooling section 34, and cascadedown, onto the lower tray(s) in counter flow with the incoming steam/airmix. Water supply channels 40 provide the cooling water for these spraynozzles 42. The cooling water quantity sprayed into the air-coolingsection 34 is about 4-5% of the total circulated cooling water.

Spray nozzles 44 in the main condenser section 45 are arranged in doublerows on the sidewalls 47 of the cooling water distributing chambers 32.The plane 49 of the baffle plates 62 (shown in FIG. 6) are inclinedrelative to the sidewalls 47 of the cooling water distributing chambers32. Consequently the water films 52 produced are also inclined. The bulkof the total cooling water (about 95%) is sprayed into the condenser 12through the spray nozzles 44 of the main section 45. The water flow ofspray nozzles 44 in the main compartment 45 of the condenser 12 is inexcess of that of the nozzles 42 in the air-cooling section 34.

Due to the inclined arrangement, the length of the water films 52 willbe longer, at a given distance between the sidewall 47 of the coolingwater distributing chambers 32 and the separating walls 46 compared withthe length of water films 52 perpendicular to the wall 47 of thedistributing chambers 32. The longer water films 52 provide larger heattransfer surface, and by these, improve the efficiency of the DCcondenser 12.

FIGS. 3 and 4 are partial cross-sectional views shown along line 3-4 ofFIG. 2 of the cooling water distributing chambers 32. Cooling waterflows through a cooling water inlet 28 into manifold 33, traversingcooling water flow paths 59 and into the cooing water distributingchamber 32. The cooling water is sprayed out of the cooling waterdistributing chamber 32 through nozzles 44. The streams of water 51 hita baffle plate 62 (shown in FIG. 6) and are diffused into thin films 52in the vertical steam channels 54. The nozzles 44, the water films 52and the vertical steam channels 54 are represented in FIGS. 3 and 4 bydiagonal hatch lines.

The baffle plate units 60 as shown in FIG. 5 can be made without anyscraps. For example, the baffle plates 62 may be cut out from a sheet 64of stainless steel on all but one side. Plastics may also be used. Thebaffle plates 62 may be bent (similar to a hinge movement) along theuncut side to extend from the sheet 64 as shown in FIGS. 5 and 6 to formopenings 66. Alternatively, the baffle plates 62 may be cut completelyfrom the sheet 64 and then fixed to the plate 64 by welding to any othersuitable method. Other techniques for fabricating the baffle units 60may also be used. The baffle units 60 may be fixed to the sidewalls 47of the cooling water distributing chambers 32 by spot welding or anyother suitable method.

FIG. 6 shows the nozzles 42, 44 attached to the sidewalls 47 via finepitch threads 69. The threads are fine enough that the nozzles 42, 44 donot require resilient members such as a gasket to attach to the wall 47in a watertight manner. The stream 51 of water is sprayed or squirtedout of the nozzles 42, 44 at a substantially right angle to the wall 47.The stream 51 hits the baffle 62 and is diffused to a fan shaped film52. As shown in FIG. 6 the diameter of the nozzles 42, 44 decreases asthe stream of water 51 exits the nozzles 42, 44.

The spray nozzles 42, 44 in accordance with the invention is illustratedin FIG. 6. The nozzle bodies 42, 44 may be a simple design, to be madeexpediently of hexagonal, stainless steel cold drawn rods. It ispossible to manufacture the required large number of nozzles 42, 44 byturning the rods on highly productive, automatic machine tools.

The baffle plates 62 are cut and punched from stainless steel strips. Abaffle plate unit 60 can consist of arbitrarily chosen number of baffleplates, 62 suitable for given size of cooling water distributionchambers 32.

In an example embodiment as shown in FIG. 7, the horizontal pitch of (orthe distance between the spray nozzles 44 is 78.3 mm in each nozzle row80 and the distance between the water films produced is 60 mm. In eachnozzle row pairs 82, 84 the lower rows 82 are offset by 39 mm relativeto the higher rows 84 of the pair, and this way the resulting distancebetween the water films 52 will be 30 mm.

In another embodiment in accordance with the invention and as shown inFIGS. 7 and 8, the inclination of the plane 49 of the baffle plates 62of the spray nozzle 44 and the water films 52 in the successive rowpairs 82, 84 are alternately oriented to the right and left. This waythe water films 52 of the successive row pairs 82, 84 are crossing eachother. In this arrangement water films 52 of the upper row pairs 82, 84cannot drop with their full length onto the water films 52 of the next,lower rows pair 82, 84. Expectedly with this arrangement the heattransfer between the condensing steam and the water films 52 isimproved.

The hydrostatic pressure in the horizontal spray nozzle rows 80 isincreasing with the decreasing geodetic height of the nozzle rows 80.Consequently the water flow of the spray nozzle 44 of the lower rows isincreased. From operating point of view this is not required, due to thefact, that the steam flow on the lower levels is less than in the higherlevels. The optimum water flow of each nozzle 80 row can be achieved byusing decreasing nozzle exit diameters in the lower nozzle rows 80.

FIG. 8 is a cross-sectional view of the wall 47 along line 8-8 shown inFIG. 7. FIG. 8 shows the baffle plates inclined to the right 72 and theleft 74 which cause water films oriented to the right 76 and the left78.

It can be seen from the aforementioned description that the spray systemand the pertaining spray nozzles 42, 44 in accordance with the presentinvention allow the implementation of more efficient and less expensiveDC condensers 12 than the currently known ones. There is no need forexpensive precision cast iron nozzles; inclined flat, turbulent waterfilms provide improved heat transfer, hence more efficient performance,and simultaneously very compact and less expensive design.

The many features and advantages of the invention are apparent from thedetailed specification, and thus, it is intended by the appended claimsto cover all such features and advantages of the invention which fallwithin the true spirit and scope of the invention. Further, sincenumerous modifications and variations will readily occur to thoseskilled in the art, it is not desired to limit the invention to theexact construction and operation illustrated and described, andaccordingly, all suitable modifications and equivalents may be resortedto, falling within the scope of the invention.

What is claimed is:
 1. A condensing system comprising: a baffle plateunit having a substantially flat surface and openings configured forcooling fluid to flow through; and baffles attached to the baffle plateunit, the baffles oriented at an acute angle with respect to the baffleplate unit, the baffles having a flat surface and figured to diffuse acooling fluid into a thin, turbulent film at a similar acute angle,wherein the baffles are aligned in longitudinal row pairs, and thebaffles of one row are longitudinally spaced by a difference of a halfpitch from the longitudinal spacing of the baffles in an immediateadjacent row, and wherein the row pairs of baffles are vertically spacedone above another and a lower row pair has nozzles having smallerdiameters than the diameters on the nozzles of the row pair above.
 2. Acondensing system comprising: a baffle plate unit having a substantiallyflat surface and openings configured for cooling fluid to flow through;baffles attached to the baffle plate unit, the baffles oriented at anacute angle with respect to the baffle plate unit, the baffles having aflat surface and figured to diffuse a cooling fluid into a thin,turbulent film at a similar acute angle; and a nozzle configured tooutlet a cooling fluid through one of the openings and substantiallyperpendicular to the substantially flat surface and contact the bafflesat an acute angle and wherein the baffles are configured to direct thecooling fluid into a flat, turbulent, fan-shaped film.
 3. The coolingsystem of claim 2, wherein the baffle plate unit is stainless steel. 4.The cooling system of claim 2, wherein the baffles are formed by cuttingthe baffle plate unit except one side and bending the cut baffles alongthis side thereby forming the baffle at the acute angle and the opening.5. The cooling system of claim 2, wherein the baffles are aligned inrows, and some rows are configured to have the baffles align in a firstdirection and other rows are configured to have the baffles align in asecond direction opposite the first direction.
 6. The cooling system ofclaim 5, wherein the system is configured to spray a cooling fluidagainst the baffles such that some of the thin films created therebywill be angled in a first direction and others of the thin films will beangled in a second direction and a fluid to be condensed by the coolingfluid constituting the thin films will flow through films angled in thefirst direction and films angled in the second direction.
 7. The coolingsystem of claim 2, wherein the baffles are aligned in longitudinal rowpairs, and the baffles of one row are longitudinally spaced by adifference of a half pitch from the longitudinal spacing of the bafflesin an immediate adjacent row.
 8. A condensing system comprising: abaffle plate unit having a substantially flat surface and openingsconfigured for cooling fluid to flow through; baffles attached to thebaffle plate unit, the baffles oriented at an acute angle with respectto the baffle plate unit, the baffles having a flat surface and figuredto diffuse a cooling fluid into a thin, turbulent film at a similaracute angle; and a nozzle configured to outlet a cooling fluid throughone of the openings wherein the nozzle is non-corrosive material and isattached to a side wall via fine pitch threads in a substantiallywatertight manner.
 9. The cooling system of claim 8, wherein the nozzlehas a hexagonal outer cross-section and the bore is dimensioned tooutlet a cooling fluid of a circular cross-section.
 10. A condensingsystem comprising: a baffle plate unit having a substantially flatsurface and openings configured for cooling fluid to flow through;baffles attached to the baffle plate unit, the baffles oriented at anacute angle with respect to the baffle plate unit, the baffles having aflat surface and figured to diffuse a cooling fluid into a thin,turbulent film at a similar acute angle; and a nozzle configured tooutlet a cooling fluid wherein the nozzle has a conical bore ofdecreasing exit diameter.
 11. A condensing system comprising: a baffleplate unit having a substantially flat surface and openings configuredfor cooling fluid to flow through; baffles attached to the baffle plateunit, the baffles oriented at an acute angle with respect to the baffleplate unit, the baffles having a flat surface and figured to diffuse acooling fluid into a thin, turbulent film at a similar acute angle; anda steam powered turbine and a power generator operatively connected tothe turbine wherein the cooling system is configured to condense thesteam exhausted by the turbine.